Air ducts, insulation, crawl spaces, attics, basements, and above ceiling spaces in offices and homes have long been a source of odors. Current products on the market to minimize odors usually contain preservatives, mild carrier solvents, and/or fragrances to attempt to mask the odors. These products are only somewhat effective.
Odor minimizing products are delivered to a substrate via the carrier solvent, and the ability of the composition to remain active in the substrate is due to a combination of the carrier solvent and surfactant. The solvents used in currently available products, however, are not sufficiently strong to allow deep penetration of the substrate. Therefore, a high concentration of the carrier solvent must be used to achieve the desired penetration. This leads to increasing levels of volatile organic compounds (VOCS) in the work place or home environment.
Certain duct odor treatment products are emulsions including a surfactant which decreases the rate of evaporation of volatile oils in the compositions. Unfortunately, neither surfactants nor surfactant combinations provide the level of stability needed in odor control compositions to inhibit evaporation of the composition while in the substrate, so that the lifespan of the product while in the substrate is severely limited. An example of such a formulation is found in Sampson et al., U.S. Pat. No. 5,085,849, which discloses an emulsified mixture of d-limonene, an ether, and water which can be used in the form of an aerosol to control odors.
Streit et al., in U.S. Pat. No. 4,178,264, disclose a gel air freshener comprising carrageenan and stearate salt, essential oils and aromatics, and a solvent component. Ethylene/polyethylene glycols and glycol mono methyl ethers are used to enhance the solubility of the stearate in processing the gel. This air freshener is not suitable for introduction into air ducts or for use on substrates, as it is a solid.
Hoppe et al.; in U.S. Pat. No. 5,895,643, describe a deodorizing composition comprising ethylene glycol monophenol ethers-2-phenoxy ethanol with Furnesol.
Rosen et al., in U.S. Pat. No. 4,844,891, disclose a preservative composition comprising mixtures of iodopropargyl compounds and a formaldehyde donor. In this case the formaldehyde donor makes it possible to use much less iodopropargyl compound than would ordinarily be necessary for preserving personal and household products.